yes
You only pay for minecraft once, and that price is $26.95. However, if you are having a minecraft server, you have to pay $10 a month.
Yes. Once you buy Minecraft, you never have to pay again unless you want to donate to a multiplayer server. But, most multiplayer servers are not affiliated with Mojang. You need only to buy the actual game once.
minecraft.net
Your own server, no unless you make other people pay to get on. Public Servers, depends on the person running the server.
First you must pay for minecraft. Then you go in multiplayer and type in the ip address for a minecraft server.
Once.
No
forever
a Hamachi server is a free version of a server to run. The owner doesnt have to pay anything to run it
No, you do not. You can host a Minecraft server as long as you have connection. Please note that you need to open your ports on your router to make a Minecraft server. If you do not have access to this, you can download a VPN-software like Hamachi or Cisco.
No, you only pay once for it.